{"cve":"CVE-2021-40839","nvd":{"published":"2021-09-10T02:15:07.933","modified":"2026-06-17T04:07:30.927","status":"Modified","description":"The rencode package through 1.0.6 for Python allows an infinite loop in typecode decoding (such as via ;\\x2f\\x7f), enabling a remote attack that consumes CPU and memory.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-835"],"references":["https://github.com/aresch/rencode/commit/572ff74586d9b1daab904c6f7f7009ce0143bb75","https://github.com/aresch/rencode/pull/29","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BMVQRPDVSVZNGGX57CFKCYT3DEYO4QB6/","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MCLETLGVM5DBX6QNHQFW6TWGO5T3DENY/","https://pypi.org/project/rencode/#history"],"products":["fedoraproject:fedora","rencode_project:rencode"],"source":"nvd","synced_at":"2026-10-19T21:23:41.316049955+00:00"},"epss":{"cve":"CVE-2021-40839","score":0.0552,"percentile":0.92807,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-gh8j-2pgf-x458","url":"https://osv.dev/vulnerability/GHSA-gh8j-2pgf-x458","summary":"Infinite Loop in rencode","modified":"2024-10-26T18:49:27.328632Z","packages":[{"ecosystem":"PyPI","name":"rencode","purl":"pkg:pypi/rencode","ranges":["<=1.0.6"],"fixed":[]}]},{"id":"PYSEC-2021-345","url":"https://osv.dev/vulnerability/PYSEC-2021-345","summary":"","modified":"2025-10-09T07:29:23.400797Z","packages":[{"ecosystem":"PyPI","name":"rencode","purl":"pkg:pypi/rencode","ranges":["all versions"],"fixed":[]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}